Antigravity device (thing)

There is a very simple way to nullify the effects of the Earth's gravity on electrons, without using any external power source. Simply put the electrons inside a long, thin, vertical metal tube which you have fixed in position. While inside the tube the electrons will not be accelerated at the usual rate

(minus sign for downwards!), but will float about at near constant velocity (until, of course, they bump into something or fly out of the tube). It helps if you evacuate the tube, since otherwise the electrons will just collide with a molecule in the air very quickly and not float about at all.

In fact, gravity is still exerting a force on the electrons
fg = g me. However, inside the bulk of the tube and (thanks to Poisson's equation) in the space enclosed, there is a (nearly) uniform electric field of magnitude
|E| = |g me/e|
directed downwards. Remembering that the charge on the electrone is negative, the electric force is fe = - g me, thus the total force, and acceleration, vanish to a very good approximation. This was experimentally tested in the second reference. Conversely, a positron in the vicinity of the tube will suffer an acceleration of 2g downwards -- falling twice as fast as usual.

Now consider the situation where a bit of metal is fixed in place within a gravitational field. The ions are, on average, held stationary by their mutual repulsion. As the conduction electrons fly about, they also feel the force of gravity, so they begin to accelerate downwards on average. They also feel lots of other forces, of course, but to begin with these average out to zero. Very soon the conduction electrons occupy a position somewhat lower than the rest of the metal. Charge separation and polarization have taken place due to gravity! There is now a net negative charge at the bottom of the piece of metal and a net positive at the top. Hence, just like inside a capacitor, there's got to be an electric field in between. In equilibrium, the size of this field is of course exactly that needed to stop the conduction electrons from drooping any farther, viz.g me/e. The authors of the first paper of course had a much more
rigorous and mathematical derivation, starting from first principles, but this is what it boils down to.

Now this is the field inside the metal; but assuming that E vanishes at infinity, we can solve the wave equation to find the field outside. For an enclosed space surrounded by metal, the solution is just a constant field, the same as the field inside the metal. Inside a sufficiently long, thin tube, it's almost exactly constant except near the ends of the tube.

Alas, in order for the same effect to work for larger bodies, you have to have the same charge to mass ratio as an electron. Even a muon is too overweight and would drop like a stone inside the tube. As pointed out in the second paper, the size of the electric field is about 5.6 × 10-11V/m: really quite small.
Besides, if even a small chunk of matter had such a concentration of electric charge, it would explode instantaneously under the electrical repulsion. Not good.